1. Field of the Invention
This specification relates to an electrode assembly for a vacuum interrupter applied to a vacuum circuit breaker.
2. Background of the Invention
In general, a vacuum interrupter is an arc-extinguishing unit used as a core component of an electric power device such as a vacuum circuit breaker, a vacuum switch, a vacuum contactor or the like, in order to break an electric load current or a fault current in an electric power system.
Among such application devices of the vacuum interrupter, the vacuum circuit breaker serves to protect an electric load in power transmission controlling and the electric power system, and since the vacuum circuit breaker has many advantages in view of a large breaking capacity and high operational reliability and stability and can be mounted in a small space, the vacuum circuit breaker has been extensively applied in voltage environments from a middle voltage to a high voltage. Also, the breaking capacity of the vacuum circuit breaker is proportionally increasing in line with the increase in the size of industrial facilities.
A vacuum interrupter of a vacuum circuit breaker operates using a magnetic field, which is generated by a current flowing through an electrode structure therein upon breaking a fault current. According to a method of generating such a magnetic field, vacuum interrupters may be divided into an Axial Magnetic Field (AMF) type and a Radial Magnetic Field (RMF) type.
An ultrahigh-voltage vacuum interrupter exhibits a very wide interval between a fixed electrode and a movable electrode in a trip (open) state and a very fast closing speed, as compared with a low-voltage vacuum interrupter. Hence, an extremely strong impact is applied to an electrode upon a closing operation. Such impact may cause a contact electrode plate, coil conductors and a supporting electrode plate to be deformed when a supporting structure for the electrodes is not satisfactory. This deformation may lower a performance of the vacuum interrupter.
FIG. 1 is a longitudinal sectional view of a vacuum interrupter according to the related art.
As shown in FIG. 1, a vacuum interrupter according to the related art may include an insulating container 1 sealed by a fixed side flange 2 and a movable side flange 3, a fixed electrode assembly 4 and a movable electrode assembly 5 received in an inner shield 6, which is fixed to an inside of the insulating container 1, and contactably facing each other, a fixing shaft 4a of the fixed electrode assembly 4 fixed onto the fixed side flange 2 and connected to the exterior, and a movable shaft 5a of the movable electrode assembly 5 slidably coupled to the movable side flange 3 and connected to the exterior.
A bellows shield 7 may be fixed onto the movable shaft 5a of the movable electrode assembly 5 and a bellows 8 may be disposed between the bellows shield 7 and the movable side flange 3, which allows the movable shaft 5a of the movable electrode assembly 5 to be movable within the insulating container 1 in a sealed state.
Here, since the fixed electrode assembly 4 and the movable electrode assembly 5 are symmetrical to each other, they are referred to as an electrode assembly 10 for explanation, hereinafter. FIG. 2 is a disassembled perspective view of the electrode assembly according to the related art.
As shown in FIG. 2, the electrode assembly 10 may include a plurality of coil conductors 131 and 135 installed between a contact electrode plate 11 and a supporting electrode plate 12, and conductor connection pins 14a to 14d installed between the contact electrode plate 11 and the coil conductors 131 and 135 or between the supporting electrode plate 12 and the coil conductors 131 and 135, respectively. The contact electrode plate 11, the coil conductors 131 and 135 and the supporting electrode plate 12 may be connected together via the conductor connection pins 14a and 14d, thereby defining a conductive path of a current.
Here, the contact electrode plate 11 and the supporting electrode plate 12 may include slits 11a and 12a (hereinafter, a slit formed at the contact electrode plate 11 is referred to as a contact side slit, and a slit formed at the supporting electrode plate is referred to as a supporting side slit) formed in a radial direction for preventing generation of an eddy current. In the AMF type vacuum interrupter, the contact side slits 11a and the supporting side slits 12a may be located in an alternating manner to create an axial magnetic flux.
Supporting pins 15a to 15d may be installed between the conductor connection pins 14a to 14d to prevent the electrode plates 11 and 12 or the coil conductors 131 and 135 from being deformed due to an impact between electrodes, which is generated upon a closing operation. The supporting pins 15a to 15d may be installed adjacent to sides of the contact side slits 11a and the supporting side slits 12a, so as to prevent deformation due to such an impact.
An unexplained reference number 16 denotes a central support, which is installed between the contact electrode plate 11 and the supporting electrode plate 12 to support a central portion.
In the electrode assembly of the vacuum interrupter according to the related art, the supporting pins 15a to 15d are installed near the contact side slits 11a and the supporting side slits 12a to prevent the deformation of the electrode plates 11 and 12 due to an impact between electrodes. However, as the contact side slits 11a and the supporting side slits 12a are formed in the alternating manner, the supporting pins 15a to 15d, which are located at both sides of the coil conductors 131 and 135 based on an axial direction, are also alternately installed. Consequently, impacts which are generated when the electrode assemblies 4 and 5 contact each other are applied at different positions. This may result in deformation of the contact electrode plate 11 and the supporting electrode plate 12 as well as the coil conductor 13 of the electrode assembly.
Also, when the number of supporting pins 15a to 15d increases to prevent the deformation, the number of components increases as well and stages of a fabricating process become complicated.